Tag Archive:
diagramming

Conditional logic can be found all over the LSAT, from Logical Reasoning to Logic Games and even occasionally in Reading Comprehension sections; therefore, understanding conditional statements and how they work is key to doing well on the LSAT. I could write a book on the ins and outs of conditional reasoning – heck, Blueprint LSAT Prep devotes several lessons to it in our course – but for now, I’ll give you a run-down of the basics.

During my time writing for this blog, I’ve repeatedly vented about my hatred for logic games. Fortunately for everyone, I won’t be talking about logic games this week; instead, I get to talk about a section that is near and dear to my heart — logical reasoning — and the dead horse that is my vendetta against logic games will get at least a weeklong reprieve. Without further adieu, here are my five quick tips for upping your logical reasoning score.

In Logic Games, cute and cuddly “A must come before B” rules are often treated as cherished instructions. It makes sense; they’re simple, absolute, and easily diagrammed. They’re also more intuitively digestible than some of our more complex Logic Games rules.

But digesting complex carbs gives you fuel, while simple carbs give you a beer belly. Similarly, complex LG rules often unlock the game and propel you through the questions, whereas “A before B” rules… make you fat… (shush, no analogy is perfect).

One of the most useful complex relationships comes in the form of an exclusive disjunction. You remember these from Logical Reasoning: “Bubba buys either laundry detergent or a whole new wardrobe, but not both.”

LSAT prep might feel like a fresh new form of torture to you, but the truth is that students have been slaving under LSAC overlords for years upon years. It just so happens that I’ve also been teaching the LSAT for a few years myself. And while each and every student I’ve taught is a special and unique snowflake, over time I’ve noticed a few trends in terms of the questions students ask most often. Now you, dear reader, can be the beneficiary of my years of accumulated wisdom. Behold, some of the most common issues faced by people studying for the LSAT:

In case you hadn’t already noticed, understanding and manipulating conditional statements is key to success on Logical Reasoning questions. If you don’t master this skill, then your target score will elude you (ya see what I did there?). In our ongoing series we’ve covered many of the trickier types of conditional statements, but today we’re going to bring it back to basics with identifying the necessary condition through what we at Blueprint call “indicator words.”

This skill is fundamental in the sense that it’s necessary (dry puns abound) in order to get your diagramming off the ground. If the necessary and sufficient conditions are misinterpreted and thus diagrammed incorrectly, transitive chains will be missed, sufficient stacks will go unnoticed, etc., etc. Most common, perhaps, is confusing which of two statements in a sentence is the sufficient and which is the necessary.

With a scurry and dash, a dodge and a slash, the No Ninja appears on the scene. Or: There She Blows, No Torpedoes the Necessary. Maybe, I don’t know…Calamatizes the Consequent, Foils the Following, what have you.

All of these mnemonics illustrate a very simple but highly effective tool for diagramming “No” statements on the LSAT. These are common conditionals, and they can come in many forms:

· No mathletes have girlfriends.
· None of the above are correct.
· Neither of them are getting her number.
· No one who dislikes Star Wars can be my friend.

Knowing how to diagram conditional claims is essential for every scored section of the LSAT. In LSAT Logical Reasoning, you have to diagram conditional claims very often with Must Be True, Must Be False, Could Be True, Sufficient, Necessary, Flaw, Parallel, and Parallel Flaw question types. In LSAT Logic Games, you’ll make some very nasty mistakes by incorrectly diagraming conditional rules. Finally, in LSAT Reading Comprehension, main points can be conditional, and many other question types will also depend on your ability to diagram.

All diagramable questions have very tempting sucker choices. This is because diagraming mistakes are easy to predict. So, an incorrect anticipation will probably show up in your answer choices. This makes diagramable questions pretty difficult.

If you want to have a successful LSAT test day, you need to learn to diagram. There are lots of ways I could say the same thing: Only if you learn to diagram will you succeed on LSAT test day, for example. Or: no one who succeeds on LSAT test day doesn’t learn to diagram.

One of the reasons diagramming is so great is that it lets you get all these statements down to the same logical structure:

Succeed on LSAT test day → Learn to diagram

Conditional statements such as the above are all over the LSAT. Many Logical Reasoning question types are chock full of them. Grouping games, especially the In and Out variety, often have nothing but conditional statements as rules. And conditional rules pop up not at all infrequently in ordering games as well.

Knowing how to identify and diagram conditional relationships is necessary for doing well on the LSAT (That is, If Do Well on LSAT -> Know how to Diagram); they are seen throughout Logical Reasoning and many of the most confusing rules in Logic Games are often conditional. If you misrepresent one of these rules, it is quite literally game over.

Learning to diagram properly may be difficult at first, and rightly so, as you’re essentially learning a new language, that of logic, but if you master this vital skill early in class you’ll have an excellent foundation for understanding future, more difficult concepts. Below are a number of harder conditional diagramming drills to help you learn this vitally important skill. Try and diagram every conditional relationship you encounter and infer any supported conclusions.

Since some crazy folks have started circulating rumors about the Logic Games on the LSAT becoming more difficult over the last year or so, I thought it might be appropriate to outline some brutal deductions.

Say hello to the final game from the September 2009 LSAT. In order to get through this game in less than an hour (and not slice your wrists in the process), some crucial deductions were needed.

Let’s take a look (the subject of the game has been slightly altered):